Links for Keyword: Brain imaging

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Andy Tay The mammalian brain consists of billions of neurons wired together in various circuits, each one involved in specific physiological functions. To better understand how these different neurons and circuits are associated with mental activities and diseases, researchers are reconstructing detailed, three-dimensional maps of neural networks. However, 3-D imaging of the mammalian brain is challenging. Light scatters as it travels through layers of tissue, dispersed by a variety of molecules such as water, lipids, and proteins. This reduces image resolution. One way to improve resolution is to reduce the scattering. Researchers achieve this by first removing water and lipids from tissue. Next, chemicals are introduced that have a refractive index—a measure of how much the molecules bend light that passes through them—in the range of that of proteins. Establishing near-homogenous refractive indices in the molecules that populate the tissue environment allows light rays to converge to improve image resolution. This is the working principle of most tissue clearing methods, which have been used successfully for decades on hard tissues like bone. Researchers have performed brain tissue clearing with limited success, as the chemicals available were too harsh on delicate neural tissues. In 2013, Karl Deisseroth and his team at Stanford University revolutionized the approach with a hydrogel-based technique called CLARITY. This technique enabled researchers to label neurons in mouse neural tissue with fluorescent markers and then to image an entire mouse brain without sectioning it, while preserving the fluorescence signals. © 1986–2019 The Scientist.

Related chapters from BN8e: Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 26718 - Posted: 10.18.2019

Mengying Zhang While many people love colorful photos of landscapes, flowers or rainbows, some biomedical researchers treasure vivid images on a much smaller scale – as tiny as one-thousandth the width of a human hair. To study the micro world and help advance medical knowledge and treatments, these scientists use fluorescent nano-sized particles. Quantum dots are one type of nanoparticle, more commonly known for their use in TV screens. They’re super tiny crystals that can transport electrons. When UV light hits these semiconducting particles, they can emit light of various colors. One nanometer is one-millionth of a millimeter. RNGS Reuters/Nanosys That fluorescence allows scientists to use them to study hidden or otherwise cryptic parts of cells, organs and other structures. I’m part of a group of nanotechnology and neuroscience researchers at the University of Washington investigating how quantum dots behave in the brain. Common brain diseases are estimated to cost the U.S. nearly US$800 billion annually. These diseases – including Alzheimer’s disease and neurodevelopmental disorders – are hard to diagnose or treat. Nanoscale tools, such as quantum dots, that can capture the nuance in complicated cell activities hold promise as brain-imaging tools or drug delivery carriers for the brain. But because there are many reasons to be concerned about their use in medicine, mainly related to health and safety, it’s important to figure out more about how they work in biological systems. © 2010–2019, The Conversation US, Inc.

Related chapters from BN8e: Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior; Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System; Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Link ID: 26708 - Posted: 10.16.2019

Jyoti Madhusoodanan Douglas Storace still has the dollar bill that he triumphantly taped above his laboratory bench seven years ago, a trophy from a successful wager. His postdoctoral mentor, Larry Cohen at Yale University in New Haven, Connecticut, bet that Storace couldn’t express a protein sensor of voltage changes in mice back in September 2012. Storace won. The bill is a handy reminder that the experiments he aims to try in his new lab can work. And it’s a testament to just how tricky it is to correctly express these sensors and track their signals. Storace, now an assistant professor at Florida State University in Tallahassee, plans to use these sensors, known as genetically encoded voltage indicators (GEVIs), to study how neurons in the olfactory bulb sense and react to smells. GEVIs are voltage-sensitive, fluorescent proteins that change colour when a neuron fires or receives a signal. Because GEVIs can be targeted to individual cells and directly indicate a cell’s electrical signals, researchers consider them to be the ideal probes for studying neurons. But they have proved frustratingly difficult to use. “Being able to visualize voltage changes in a cell has always been the dream,” says neuroscientist Bradley Baker at the Korea Institute of Science and Technology in Seoul. “But probes that looked great often didn’t behave in ways that were useful.” Early GEVIs disappointed on several levels. They were bright when a cell was resting and dimmed when the cell fired an action potential, producing signals that were tough to distinguish from the background. And they failed to concentrate in the nerve-cell membranes, where they function. But researchers are beginning to solve these issues. Some are turning to advanced fluorescent proteins or chemical dyes for better signals; others are using directed evolution and high-throughput screens to make GEVIs more sensitive to voltage changes. Meanwhile, biologists are putting these molecules through their paces. GEVIs, says neuroscientist Katalin Toth at Laval University in Quebec City, Canada, are not yet widely used, but they’re getting there. “They are becoming brighter and faster — and growing in popularity,” she says. “I think this is the dawn of GEVIs.” © 2019 Springer Nature Limited

Related chapters from BN8e: Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals; Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior
Related chapters from MM:Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals; Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 26703 - Posted: 10.15.2019

By Laura Sanders Survey any office, and you’ll see pens tapping, heels bouncing and hair being twiddled. But jittery humans aren’t alone. Mice also fidget while they work. What’s more, this seemingly useless motion has a profound and widespread effect on mice’s brain activity, neuroscientist Anne Churchland of Cold Spring Harbor Laboratory in New York and colleagues report September 24 in Nature Neuroscience. Scientists don’t yet know what this brain activity means, but one possibility is that body motion may actually shape thinking. Researchers trained some mice to lick a spout corresponding to an area where a click or a flash of light originated. To start their task, mice grabbed a handle and waited for the signal. As the mice focused on their jobs, researchers used several different methods to eavesdrop on nerve cell behavior in the animals’ brains. All the while, video cameras and a sensor embedded on a platform under the mice picked up every move the rodents made — and there were a lot. Mice wiggled their noses, flicked their whiskers and fiddled their hind paws while concentrating on finding the sound or light, the team found. Those fidgets showed up in nerve cell activity. When a whisker moved, for instance, nerve cells involved in moving and sensing sprang into action. Fidgets predicted a big chunk of neural behavior, mathematical models suggested. Mice’s fidgets even had stronger effects on brain activity than did the task at hand, the researchers report. © Society for Science & the Public 2000–2019

Related chapters from BN8e: Chapter 11: Motor Control and Plasticity; Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior
Related chapters from MM:Chapter 5: The Sensorimotor System; Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 26653 - Posted: 09.28.2019

Ian Sample Science editor Society must prepare for a technological revolution in which brain implants allow people to communicate by telepathy, download new skills, and brag about their holidays in “neural postcards”, leading scientists say. While such far-fetched applications remain fiction for now, research into brain implants and other neural devices is advancing so fast that the Royal Society has called for a “national investigation” into the technology. “In 10 years’ time this is probably going to touch millions of people,” said Tim Constandinou, director of the next generation neural interfaces lab at Imperial College London, and co-chair of a new Royal Society report called iHuman. “These technologies are not possible today, but we are heading in that direction.” A neuroscientist explains: the need for ‘empathetic citizens’ - podcast The report foresees a “neural revolution” driven by electronic implants that communicate directly with the brain and other parts of the nervous system. By 2040, the scientists anticipate that implants will help the paralysed to walk, with other devices alleviating the symptoms of neurodegenerative diseases and treatment-resistant depression. The new wave of devices will go beyond existing products such as cochlear implant hearing aids and deep brain stimulators for people with Parkinson’s disease, with gadgets that help the healthy. In research labs, scientists are working on ways for people to type with their brains, and share thoughts by connecting their minds. Other teams are developing helmets and headbands to speed up learning and improve memory. “People could become telepathic to some degree, able to converse not only without speaking but without words, through access to each other’s thoughts at a conceptual level. This could enable unprecedented collaboration with colleagues and deeper conversations with friends,” the report states. © 2019 Guardian News & Media Limited

Related chapters from BN8e: Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals; Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals; Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 26595 - Posted: 09.10.2019

By Eryn Brown, On March 30, 1981, 25-year-old John W. Hinckley Jr. shot President Ronald Reagan and three other people. The following year, he went on trial for his crimes. Defense attorneys argued that Hinckley was insane, and they pointed to a trove of evidence to back their claim. Their client had a history of behavioral problems. He was obsessed with the actress Jodie Foster, and devised a plan to assassinate a president to impress her. He hounded Jimmy Carter. Then he targeted Reagan. In a controversial courtroom twist, Hinckley’s defense team also introduced scientific evidence: a computerized axial tomography (CAT) scan that suggested their client had a “shrunken,” or atrophied, brain. Initially, the judge didn’t want to allow it. The scan didn’t prove that Hinckley had schizophrenia, experts said—but this sort of brain atrophy was more common among schizophrenics than among the general population. It helped convince the jury to find Hinckley not responsible by reason of insanity. Nearly 40 years later, the neuroscience that influenced Hinckley’s trial has advanced by leaps and bounds—particularly because of improvements in magnetic resonance imaging (MRI) and the invention of functional magnetic resonance imaging (fMRI), which lets scientists look at blood flows and oxygenation in the brain without hurting it. Today neuroscientists can see what happens in the brain when a subject recognizes a loved one, experiences failure, or feels pain. Despite this explosion in neuroscience knowledge, and notwithstanding Hinckley’s successful defense, “neurolaw” hasn’t had a tremendous impact on the courts—yet. But it is coming. Attorneys working civil cases introduce brain imaging ever more routinely to argue that a client has or has not been injured. Criminal attorneys, too, sometimes argue that a brain condition mitigates a client’s responsibility. Lawyers and judges are participating in continuing education programs to learn about brain anatomy and what MRIs and EEGs and all those other brain tests actually show. © 2019 Scientific American

Related chapters from BN8e: Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior; Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System; Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 26587 - Posted: 09.09.2019

Jon Hamilton In mice, scientists have used a variety of drugs to treat brain disorders including murine versions of Alzheimer's disease, depression and schizophrenia. But in people, these same treatments usually fail. And now researchers are beginning to understand why. A detailed comparison of the cell types in mouse and human brain tissue found subtle but important differences that could affect the response to many drugs, a team reports Wednesday in the journal Nature. "If you want to develop a drug that targets a specific receptor in a specific disease, then these differences really matter," says Christof Koch, an author of the study and chief scientist and president of the Allen Institute for Brain Science in Seattle. One key difference involved genes that cause a cell to respond to the chemical messenger serotonin, says Ed Lein, a study author and investigator at the institute. "They're expressed in both mouse and human, but they're not in the same types of cells," Lein says. As a result, "serotonin would have a very different function when released into the cortex of the two species." That's potentially a big deal because antidepressants like Prozac act on the brain's serotonin system. So testing these drugs on mice could be misleading, Lein says. The comparison was possible because of new technology that allows scientists to quickly identify which of the hundreds of types of brain cells are present in a particular bit of brain tissue. © 2019 npr

Related chapters from BN8e: Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 26530 - Posted: 08.22.2019

Laura Sanders The golf ball–sized chunk of brain is not cooperating. It’s thicker than usual, and bloodier. One side has a swath of tissue that looks, to my untrained eye, like gristle. Nick Dee, the neuroscientist charged with quickly cutting the chunk into neat pieces, confers with his colleagues. “We can trim off that ugliness on the side,” he says. The “ugliness” is the brain’s connective tissue called white matter. To produce useful slices for experiments, the brain tissue must be trimmed, superglued to a lipstick-sized base and then fed into a lab version of a deli slicer. But this difficult chunk isn’t cutting nicely. Dee and colleagues pull it off the base, trim it again and reglue. Half an hour earlier, this piece of neural tissue was tucked inside a 41-year-old woman’s head, on her left side, just above the ear. Surgeons removed the tissue to reach a deeper part of her brain thought to be causing severe seizures. Privacy rules prevent me from knowing much about her; I don’t know her name, much less her first memory, favorite meal or sense of humor. But within this piece of tissue, which the patient generously donated, are clues to how her brain — all of our brains, really — create the mind. Dee’s team is working fast because this piece of brain is alive. Some of the cells can still behave as if they are a part of a person’s brain, which means they hold enormous potential for scientists who want to understand how we remember, plan, behave and feel. After Dee and his team do their part, pieces of the woman’s brain will be whisked into the hands of eager scientists, where the cells will be photographed, zapped with electricity, relieved of their genetic material and even infected with viruses that make them glow green and red. © Society for Science & the Public 2000 - 2019

Related chapters from BN8e: Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 26490 - Posted: 08.12.2019

Ian Sample Science editor Doctors have turned the brain signals for speech into written sentences in a research project that aims to transform how patients with severe disabilities communicate in the future. The breakthrough is the first to demonstrate how the intention to say specific words can be extracted from brain activity and converted into text rapidly enough to keep pace with natural conversation. In its current form, the brain-reading software works only for certain sentences it has been trained on, but scientists believe it is a stepping stone towards a more powerful system that can decode in real time the words a person intends to say. A neuroscientist explains: the need for ‘empathetic citizens’ - podcast Doctors at the University of California in San Francisco took on the challenge in the hope of creating a product that allows paralysed people to communicate more fluidly than using existing devices that pick up eye movements and muscle twitches to control a virtual keyboard. “To date there is no speech prosthetic system that allows users to have interactions on the rapid timescale of a human conversation,” said Edward Chang, a neurosurgeon and lead researcher on the study published in the journal Nature. The work, funded by Facebook, was possible thanks to three epilepsy patients who were about to have neurosurgery for their condition. Before their operations went ahead, all three had a small patch of tiny electrodes placed directly on the brain for at least a week to map the origins of their seizures. © 2019 Guardian News & Media Limited

Related chapters from BN8e: Chapter 19: Language and Lateralization; Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior
Related chapters from MM:Chapter 15: Brain Asymmetry, Spatial Cognition, and Language; Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 26472 - Posted: 07.31.2019

Abby Olena For years, scientists thought the brain lacked a lymphatic system, raising questions about how fluid, macromolecules, and immune cells escape the organ. In 2015, two studies in mice provided evidence that the brain does in fact have a traditional lymphatic system in the outermost layer of the meninges—the coverings that protect the brain and help keep its shape—but scientists hadn’t yet figured out the exact exit route cerebrospinal fluid (CSF) and molecules take. In a study published today (July 24) in Nature, researchers show that there is a hot spot of meningeal lymphatic vessels at the base of the rodent skull that is specialized to drain CSF and allow proteins and other large molecules to leave the brain. “What they showed very nicely is that the system of meningeal lymphatics is the drainage system of the CSF of the central nervous system,” says Jonathan Kipnis, a neuroscientist at the University of Virginia who did not participate in the new study, but coauthored the first 2015 study. “We’re just scratching really the surface of understanding what these vessels are doing.” “I’m actually quite relieved because when we published in 2015 . . . we got a lot of contrasting comments and some people were not convinced that the lymphatics really can be involved in cerebrospinal fluid drainage because there was a lot of literature telling otherwise,” Kari Alitalo of the University of Helsinki tells The Scientist. Alitalo coauthored the second 2015 paper describing the brain’s lymphatic system, but was not involved in the current study. © 1986–2019 The Scientist

Related chapters from BN8e: Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 26452 - Posted: 07.26.2019

Ian Sample Science editor Brain scans of US embassy staff who became ill in mysterious circumstances while serving in Cuba have found potential abnormalities that may be related to their symptoms. The scans taken from 40 US government workers who suffered strange concussion-like symptoms during their deployment to Havana revealed that particular brain features looked different to those in healthy volunteers. Images of the diplomats’ brains found that on average they had lower volumes of white matter, the tissue made from nerve bundles that send messages around the brain. They also showed micro-structural differences and other changes that could affect auditory and visuospatial processing, doctors said. But the medical team that performed the scans said the findings were not conclusive. They do not match what is normally seen in brain injuries and the severity of symptoms did not vary with the extent of the brain differences spotted. “It’s a unique presentation that we have not seen before,” said Ragini Verma, a professor of biomedical imaging on the team at the University of Pennsylvania. “What caused it? I’m completely unequipped to answer that.” Independent experts agreed the findings were inconclusive and said it was still unclear whether the diplomats were victims of any attack or had suffered related brain injuries. The apparent abnormalities might have pre-dated the attacks, they said, and could have more mundane explanations such as anxiety or depression. One said the study did not meet the usual standards for publication. © 2019 Guardian News & Media Limited

Related chapters from BN8e: Chapter 19: Language and Lateralization; Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior
Related chapters from MM:Chapter 15: Brain Asymmetry, Spatial Cognition, and Language; Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 26446 - Posted: 07.24.2019

Ed Yong On July 22, 2009, the neuroscientist Henry Markram walked onstage at the TEDGlobal conference in Oxford, England, and told the audience that he was going to simulate the human brain, in all its staggering complexity, in a computer. His goals were lofty: “It’s perhaps to understand perception, to understand reality, and perhaps to even also understand physical reality.” His timeline was ambitious: “We can do it within 10 years, and if we do succeed, we will send to TED, in 10 years, a hologram to talk to you.” If the galaxy-brain meme had existed then, it would have been a great time to invoke it. It’s been exactly 10 years. He did not succeed. One could argue that the nature of pioneers is to reach far and talk big, and that it’s churlish to single out any one failed prediction when science is so full of them. (Science writers joke that breakthrough medicines and technologies always seem five to 10 years away, on a rolling window.) But Markram’s claims are worth revisiting for two reasons. First, the stakes were huge: In 2013, the European Commission awarded his initiative—the Human Brain Project (HBP)—a staggering 1 billion euro grant (worth about $1.42 billion at the time). Second, the HBP’s efforts, and the intense backlash to them, exposed important divides in how neuroscientists think about the brain and how it should be studied. Markram’s goal wasn’t to create a simplified version of the brain, but a gloriously complex facsimile, down to the constituent neurons, the electrical activity coursing along them, and even the genes turning on and off within them. From the outset, the criticism to this approach was very widespread, and to many other neuroscientists, its bottom-up strategy seemed implausible to the point of absurdity.

Related chapters from BN8e: Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 26440 - Posted: 07.23.2019

By Tanya Lewis Late on Tuesday evening, Elon Musk, the charismatic and eccentric CEO of SpaceX and Tesla, took to the stage at the California Academy of Sciences to make a big announcement. This time, he was not unveiling a new rocket or electric car but a system for recording the activity of thousands of neurons in the brain. With typical panache, Musk talked about putting this technology into a human brain by as early as next year. The work is the product of Neuralink, a company Musk founded in 2016 to develop a high-bandwidth, implantable brain-computer interface (BCI). He says the initial goal is to enable people with quadriplegia to control a computer or smartphone using just their thoughts. But Musk’s vision is much more ambitious than that: he seeks to enable humans to “merge” with AI, giving people superhuman intelligence—an objective that is much more hype than an actual plan for new technology development. Neuralink prototype device. Credit: Neuralink On a more practical note, “the goal is to record from and stimulate [signals called] spikes in neurons” with an order of magnitude more bandwidth than what has been done to date and to have it be safe, Musk said at Tuesday’s event, which was livestreamed. Advertisement The system unveiled last night was a long way from Musk’s sci-fi vision. But it was nonetheless marked an impressive technical development. The team says it has now developed arrays with a very large number of “channels”—up to 3,072 flexible electrodes—which can be implanted in the brain’s outer layer, or cortex, using a surgical robot (a version of which was described as a “sewing machine” in a preprint paper posted on bioRxiv earlier this year). The electrodes are packaged in a small, implantable device containing custom-built integrated circuits, which connects to a USB port outside the brain (the team hopes to ultimately make the port wireless). © 2019 Scientific American

Related chapters from BN8e: Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior; Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System; Chapter 5: The Sensorimotor System
Link ID: 26427 - Posted: 07.18.2019

Laura Sanders Over 100 hours of scanning has yielded a 3-D picture of the whole human brain that’s more detailed than ever before. The new view, enabled by a powerful MRI, has the resolution potentially to spot objects that are smaller than 0.1 millimeters wide. “We haven’t seen an entire brain like this,” says electrical engineer Priti Balchandani of the Icahn School of Medicine at Mount Sinai in New York City, who was not involved in the study. “It’s definitely unprecedented.” The scan shows brain structures such as the amygdala in vivid detail, a picture that might lead to a deeper understanding of how subtle changes in anatomy could relate to disorders such as post-traumatic stress disorder. To get this new look, researchers at Massachusetts General Hospital in Boston and elsewhere studied a brain from a 58-year-old woman who died of viral pneumonia. Her donated brain, presumed to be healthy, was preserved and stored for nearly three years. Before the scan began, researchers built a custom spheroid case of urethane that held the brain still and allowed interfering air bubbles to escape. Sturdily encased, the brain then went into a powerful MRI machine called a 7 Tesla, or 7T, and stayed there for almost five days of scanning. |© Society for Science & the Public 2000 - 2019.

Related chapters from BN8e: Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 26401 - Posted: 07.09.2019

By Knvul Sheikh The tiny, transparent roundworm known as Caenorhabditis elegans is roughly the size of a comma. Its entire body is made up of just about 1,000 cells. A third are brain cells, or neurons, that govern how the worm wriggles and when it searches for food — or abandons a meal to mate. It is one of the simplest organisms with a nervous system. The circuitry of C. elegans has made it a common test subject among scientists wanting to understand how the nervous system works in other animals. Now, a team of researchers has completed a map of all the neurons, as well as all 7,000 or so connections between those neurons, in both sexes of the worm. “It’s a major step toward understanding how neurons interact with each other to give rise to different behaviors,” said Scott Emmons, a developmental biologist at the Albert Einstein College of Medicine in New York who led the research. Structure dictates function in several areas of biology, Dr. Emmons said. The shape of wings provided insight into flight, the helical form of DNA revealed how genes are coded, and the structure of proteins suggested how enzymes bind to targets in the body. It was this concept that led biologist Sydney Brenner to start cataloging the neural wiring of worms in the 1970s. He and his colleagues preserved C. elegans in agar and osmium fixative, sliced up their bodies like salami and photographed their cells with a powerful electron microscope. © 2019 The New York Times Company

Related chapters from BN8e: Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System; Chapter 13: Memory, Learning, and Development
Link ID: 26389 - Posted: 07.04.2019

Sara Reardon A medical imaging device that can create 3D renderings of the entire human body in as little as 20 seconds could soon be used for a wide variety of research and clinical applications. The modified positron emission tomography (PET) scanner is faster than conventional PET scans — which can take an average of 20 minutes — and requires less radiation exposure for the person being imaged. Researchers presented video taken by the device last week at the US National Institutes of Health’s High-Risk, High-Reward Research Symposium in Bethesda, Maryland. The machine could be especially helpful for imaging children, who tend to wiggle around inside a scanner and ruin the measurements, as well as for studies of how drugs move through the body, says Sanjay Jain, a paediatrician and infectious-disease physician at Johns Hopkins University in Baltimore, Maryland. Standard PET scanners detect γ-rays from radioactive tracers that doctors inject into the person being imaged. The person’s cells take up the molecule and break it down, releasing two γ-rays. A ring-shaped detector positioned around the person measures the angle and speed of the rays and reconstructs their origin, creating a 3D map of the cells that are metabolizing the molecule. The ring is just 25 centimetres thick, however, so physicians can image only a small portion of the body at a time. Capturing larger areas requires them to dose the person with more of the radioactive molecule ― it decays quickly, which means the signal fades fast ― and move them back and forth through the ring. © 2019 Springer Nature Publishing AG

Related chapters from BN8e: Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 26328 - Posted: 06.14.2019

By Kelly Servick For a hair-thin probe penetrating the brain to listen in on neurons' electrical chatter, finesse is key. It's easy to rip tissue on the way in. And once in place, a probe can do further damage that muffles the signals it aims to detect. But recent reports describe a generation of finer probes that should prove less damaging. Just a few micrometers thick—comparable to neurons themselves—these tools may soon capture unprecedented long-term recordings from hard-to-reach parts of animal brains. And they may lead to more sophisticated brain-computer interfaces for people. Improved material fabrication techniques have helped labs create the exquisitely fine probes, says neural engineer Timothy Hanson, who developed a system for inserting tiny electrodes while at the University of California, San Francisco (UCSF). And lab tests have shown that brain research using ultrasmall electrodes "can be done, and that it's worthwhile." Conventional brain probes are already vanishingly tiny. Stiff electrodes known as Michigan probes, commonly used in neuroscience research, are pointed, ribbonlike shafts that can be as thin as 15 micrometers and are usually 60 micrometers wide or more. In a standard grid known as the Utah array, each spike is roughly 200 micrometers thick at its base. But in the months after either device is implanted, its connection to neurons typically weakens and its signal fades. A key reason is that the probe provokes an immune reaction in the brain. Its initial plunge into the tissue can tear blood vessels. And even after that damage heals, the probe continues to push and pull on surrounding tissue. In response, nonneuronal cells called glia multiply and form scars that push neurons away from the electrode. © 2019 American Association for the Advancement of Science.

Related chapters from BN8e: Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Related chapters from MM:Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Link ID: 26200 - Posted: 05.02.2019

By Karen Weintraub Stroke, amyotrophic lateral sclerosis and other medical conditions can rob people of their ability to speak. Their communication is limited to the speed at which they can move a cursor with their eyes (just eight to 10 words per minute), in contrast with the natural spoken pace of 120 to 150 words per minute. Now, although still a long way from restoring natural speech, researchers at the University of California, San Francisco, have generated intelligible sentences from the thoughts of people without speech difficulties. The work provides a proof of principle that it should one day be possible to turn imagined words into understandable, real-time speech circumventing the vocal machinery, Edward Chang, a neurosurgeon at U.C.S.F. and co-author of the study published Wednesday in Nature, said Tuesday in a news conference. “Very few of us have any real idea of what’s going on in our mouth when we speak,” he said. “The brain translates those thoughts of what you want to say into movements of the vocal tract, and that’s what we want to decode.” But Chang cautions that the technology, which has only been tested on people with typical speech, might be much harder to make work in those who cannot speak—and particularly in people who have never been able to speak because of a movement disorder such as cerebral palsy. Chang also emphasized that his approach cannot be used to read someone’s mind—only to translate words the person wants to say into audible sounds. “Other researchers have tried to look at whether or not it’s actually possible to decode essentially just thoughts alone,” he says.* “It turns out it’s a very difficult and challenging problem. That’s only one reason of many that we focus on what people are trying to say.” © 2019 Scientific American

Related chapters from BN8e: Chapter 19: Language and Lateralization; Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior
Related chapters from MM:Chapter 15: Brain Asymmetry, Spatial Cognition, and Language; Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 26170 - Posted: 04.24.2019

By Kelly Servick The machines that scan our brains are usually monstrous contraptions, locked away in high-end research centers. But smaller, cheaper technologies may soon enter the field, like an MRI scanner built for the battlefield and a lightweight, wearable magnetoencephalography system that records magnetic fields generated by the brains of people in motion. If such devices become widespread, they’ll raise new ethical questions, says Francis Shen, a law professor and neuroethicist at the University of Minnesota (UMN) in Minneapolis and Massachusetts General Hospital in Boston. How should researchers share results with the far-flung populations they may soon be able to study? Could direct-to-consumer neuroimaging become an industry alongside personal genetic testing? With a grant from the federal Brain Research through Advancing Innovative Neurotechnologies (BRAIN) Initiative, Shen has teamed up with three UMN colleagues, including MRI physicist Michael Garwood, to start a conversation about the ethical implications of portable neuroimaging. Garwood is part of a multicenter team building an MRI machine powerful enough to be used in medical diagnostic tests that weighs just 400 kilograms—less than a tenth of traditional scanners. He expects the new scanner to take its first images in 3 years. And if market demand can bring down the cost of a key component, he thinks it could eventually cost $200,000 or less, versus millions of dollars for current scanners. Shen and Garwood discussed the ethical issues at play with Science, after presenting their work at a meeting of BRAIN Initiative investigators last week in Washington, D.C. This interview has been edited for brevity and clarity. © 2019 American Association for the Advancement of Science

Related chapters from BN8e: Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 26149 - Posted: 04.17.2019

By Kelly Servick At age 16, Danielle Bassett spent most of her day at the piano, trying to train her fingers and ignoring a throbbing pain in her forearms. She hoped to pursue a career in music and had been assigning herself relentless practice sessions. But the more she rehearsed Johannes Brahms's feverish Rhapsody in B Minor on her family's Steinway, the clearer it became that something was wrong. Finally, a surgeon confirmed it: Stress fractures would force her to give up the instrument for a year. "What was left in my life was rather bleak," Bassett says. Her home-schooled upbringing in rural central Pennsylvania had instilled a love of math, science, and the arts. But by 17, discouraged by her parents from attending college and disheartened at her loss of skill while away from the keys, she expected that responsibilities as a housewife and mother would soon eclipse any hopes of a career. "I wasn't happy with that plan," she says. Instead, Bassett catapulted herself into a life of research in a largely uncharted scientific field now known as network neuroscience. A Ph.D. physicist and a MacArthur fellow by age 32, she has pioneered the use of concepts from physics and math to describe the dynamic connections in the human brain. "She's now the doyenne of network science," says theoretical neuroscientist Karl Friston of University College London. "She came from a formal physics background but was … confronted with some of the deepest questions in neuroscience." © 2019 American Association for the Advancement of Science.

Related chapters from BN8e: Chapter 2: Functional Neuroanatomy: The Nervous System and Behavior; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System; Chapter 13: Memory, Learning, and Development
Link ID: 26133 - Posted: 04.12.2019